Sewing machine throat-plate mechanisms



Jan. 12, 1960 R. E. JOHNSON 2,920,593

srswmc MACHINE THROAT-PLATE MECHANISMS Original Filed Nov. 29', 1954 isheets-sheet INVENTOR. Ralph E. Johnson ATTORNEY Jan. 12, 1960 R. E. JOHNSON 7 2,920,593

SEWING MACHINE THROAT-PLATE MECHANISMS Original Filed Nov. 29, 1954 3 Sheets-Sheet 2 INVENTOR. Ralph E. Johnson A TTORNE Y Jan. 12', 1960 R. E. JOHNSON SEWING MACHINE THROAT-PLATE MECHANISMS Original Filed Nov. 29

3 Sheets-Sheet 3 mmvroa Ralph E. Johnson ATTORNEY United States Patent Ofifice 2,920,593 Patented Jan. 12, 1960 MACHINE THROAT-PLATE MECHANISMS Ralph E. Johnson, Mountainside, N.J., assignor to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey SEWING 8 Claims. (Cl. 112-260) This invention relates to sewing machines and more particularly to improvements in throat-plate devices especially adapted for use with family type sewing machines. The present throat-plate mechanism is designed to inactivate a sewing machine work-feeding mechanism when it is desired to use the machine for darning, embroidering and other similar operations, and to reactivate the feeding mechanism when the machine is to be used for ordinary sewing operations.

Another object of the invention is to provide means for inactivating a sewing machine feeding mechanism, which means will be quicker and easier to operate and more positive in its action than similar devices heretofore used.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attainedthereby will be readily understood by those skilled in the art. In the accompanying drawings:

Fig. 1 represents a front perspective view of a sewing machine in which the present invention is embodied.

Fig. 2 represents a vertical sectional view through the left-hand end of the machine frame illustrated in Fig. 1.

Fig.- 3 represents a top plan view of a portion of the sewing machine bed illustrating a portion of the bed with its slide plate partially removed and with its throat-plate entirely removed.

Fig. 4 represents a top plan view of a throat-plate provided with an aperture for the reception of an endwise reciprocatory needle.

Fig. 5 represents, on an enlarged scale, a fragmentary bottom plan view of the machine as illustrated in Fig. 1.

Fig. 6 represents, on an enlarged scale, a sectional view taken substantially along the line 6-6 of Fig. 5.

Figs. 7 and 8 represent a portion of the throat-plate lifting mechanism in different stages of its operation.

Fig. 9 represents, on an enlarged scale, a sectional view taken substantially on the line 9-9 of Fig. 5.

Fig. 10 illustrates an indicia plate which, as illustrated in Fig. 1, is adapted to be secured to the bed of a sewing machine proper.

The following detailed description has to do with a construction of a throat-plate mechanism as it relates to a sewing machine of the type disclosed in my co-pending application Serial No. 471,766, filed November 29, 1954, now Patent No. 2,862,468, granted December 2, 1958, of which this application is a division.

As illustrated in the drawings, the frame of the sewing machine in which the present invention is incorporated comprises a substantially rectangular shaped base formwardly extending side walls 11-11 and end walls 12-12 forming a box-like enclosure.

Suitably secured upon the hollow bed 10 is a'vertically disposed hollow standard 13 carrying an overhanging bracket-arm 14 terminating in a hollow head 15 in which 'is mounted a reciprocatory needle-bar 16 and a presser-bar 17. A needle 18 is carried. by the needle bar 16. A main driving shaft (not herein shown) is disposed within and lengthwise of the overhanging bracket arm 14 for actuating the needle bar 16. The standard end of the main driving shaft is connected with a hand wheel 19 in a-manner which is best disclosed in US. Patent No. 2,617,375 dated November 11, 1952.

The main driving shaft rotates a loop-taker actuating shaft 20 (see Fig. 5) by way of a vertical shaft 21 and bevel gears 22 and 23. This loop-taker actuating shaft 20 is suitably journaled in bearings 24 and 25 mounted on the base of the machine.

Means, not herein shown, are provided for oscillating shafts 26 and 27 which are mounted within the machine base. These shafts 26 and 27 actuate a conventional feeddog 28 by way of a feed-bar 29 which is connected with the shafts by cranks 30 and 31 of which the latter is connected to the bar 29 by means of a link 32.

The needle 18 is adapted to cooperate in the formation of a lock stitch with a rotary loop-taker 33 disposed beneath the bed 10. Mounted upon the lower end of the presser-bar 17 is a conventional type of presser-foot 34 which cooperateswith a throat-plate 35 and the feed-dog 28 in the feeding of the work over the bed 10 and away from the operator. =The throat-plate 35is carried by the work support 10.

Referring particularly to Figs. 1 and 3, the bed 10 is provided above the rotary loop-taker 33 with an opening generally designated by the numeral 36, which opening is defined by a recessed ledge 37 which supports the conventional type of slide plate 38 which may be shifted back and forth so as to cover the loop-taker in the manner as is disclosed in Fig. 1 or to give access to the loop-taker in the manner as is disclosed in Fig. 3. The rear portion of the opening 36 beneath the presser foot 34 is adapted to be covered by means of the throat plate 35 which, as is shown in Fig. 4, is provided with a needle aperture 39 and apertures 40, 41 and 42 which receive the feed-dog 28.

As is best illustrated in Figs. 2 and 3, the feed dog 28 is carried by the feed bar 29 which extends over the looptaker 33. From this, it is to be understood that the rotary loop-taker is disposed substantially in front of the feeding mechanism as well as in front of the reciprocatory needle 18 so that the operator may have ready access to the loop-taker mechanism.

Fig. 1 illustrates the normal position taken by the throat-plate 35 which, as hereinabove described, is disposed within the bed opening 36 and upon the inwardly directed opening ledge 37. As illustrated in Fig. 4, the throat-plate 35 is provided at either side thereof with a slight indentation 43-43 each of which is adapted to be received within a slot 44 formed within a respective one of a pair of plungers 45 and 46 which normally function to maintain the throat plate 35 in its operative position as is best illustrated in Figs. 1 and 6.

Each of the plungers 45 and 46 is slidingly mounted in a respective one of a pair of cylindrical bores 47 and 48 formed within depending members 49 and 50 of the bed 1. 45 and 46 is provided with a collar 51 against which one end of a coil spring 52 is adapted to be biased. The upper end of the spring 52 which surrounds the plunger 45 engages .the upper shoulder 53 of a bore 54 while the upper end of the spring 52 surrounding the plunger 46 engages a shoulder 55 formed on the member 50. From this, it is to be understood that the springs 52, 52 function to bias the plungers 45, 46 downwardly there- The lower portion of each of the plungers by to maintain the throat plate 35 in its operative position.

The present invention contemplates the provision of means whereby the throat plate 35- may be elevated toa position abovethe bed 10 so as to render the feed-dogZS ineffective due to the fact that the latter can no longer project above the surface of the throat-plate for the purpose of feeding the work. Such an elevated position of the throat-plate is particularly disclosed in Fig. 7. With the throat-plate 35 so raised above the feed-dog, the latter is rendered ineffective and thus the operator may perform various types of ornamental stitching, the execution of which requires that the work be hand fed beneath the needle and over the throat-plate. Furthermore, those skilled in the art will readily understand that most ornamental stitching of this latter type is accomplished with the use of darning hoops for stretching and maintaining the work in a taut position and that with the present throat-plate 35 raised above the normal level of the bed 10, the throat-plate will function to bias the work upwardly over the normal bed level and thereby stretch the same relative to the darning hoops to the end the work will be prevented from flagging during the stitching operations.

Referring particularly to Figs. 6, 7, 8, each of the plungers 45 and 46 is provided with a hollow bore 56 in which is slidingly mounted a plunger pin 57 which normally under the force of gravity rests upon the upper surface of a cam bar generally designated by the numeral 58. The upper surface 59 of the cam bar 58 is provided with a pair of laterally spaced raised cam surfaces generally designated by the numerals 60 and 61. Also, the under surface 62 of the cam bar is provided with a dependingcam surface designated by the numeral 63. As-may be observed from Figs. and 6, the cam bar 53 at its left-hand portion rests upon the upper surface of a screw 64 which is threaded directly within the lower portion of the depending member 49 which is provided with a slot 65 for receiving and guiding the cam bar 58.

As may be observed from Fig. 5, an intermediate portion of the cam bar 58 is guided within a slot 66 formed within a depending frame portion 67. The extreme right,- hand end portion of the cam bar 58 is bent in the shape of an upright U as at 68 and supported within the opposite limbs of the U is a shoulder screw 69, an intermediate portion of which pivotally supports a handle 70 whose lower end portion 71 is bent in the shape of an eye and surrounds the shoulder screw 69. Intermediate the length of the handle 70 is formed oppositely extending pintle members 72-72 which are supported within the upturned end portions 73-73 of the forked end of a support arm 74 which is secured to the sewing machine bed by means of ascrew 75.

As may be best observed in Figs. 5 and 6, the upper portion of the handle 70 extends through the bed 10 by way' of a bed aperture 76 so as to be accessible to the operator in a manner as is best disclosed in Fig. 1. From this, it will be appreciated that the member 74 acts as a pivotal support for the arm 70 to the end that the free end portion of the arm may be swung from left to right thereby to effect a left to a right reciprocatory motion of the cam bar 58.

With the handle member 70 at its extreme right-hand position as illustrated in Fig. 9, the cam bar 58 is dis.- posed in the positionas illustrated in Fig. 6 wherein the throat plate 35 is adapted to be disposed in its lowest or normal position. However, when the handle member 70 is shifted to an intermediate position as illustrated by the dotted lines generally designated by the numeral 70", the cam bar is shifted to the right so that the lower cam surface 63 of the bar is ina positionon top of the-support screw 64 and the upper. flatv portion ofthe lefthand cam 60; engages. thepin', 57 so. as to elevate the same and the right-hand inclined portion 77 of the cam 60 engages the under surface of the plunger shoulder. ;51

4 so as to elevate the entire plunger 45 tain the throat-plate in a position as is illustrated in Fi 7.

%By the same token, the right-hand cam 61 is positioned relative to the right-hand plunger 46 so that the upper fiat surface of the cam will bias the pin 57 upwardly and the right-hand inclined portion 78 of the cam 61 will bias the plunger 46 upwardly in the same manner as illustrated in Fig.- 7 in connection with the plunger 45. The throat-plate is locked in this raised position. by being clamped between the plungers 45, 46 and their associated plunger pins 5757.

When it is desired to remove the throat-plate 35 from the sewing machine, the operator merely shifts the handle member 70 to the left-hand dotted line position generally designated by the numeral 79. When in this position, the cam bar 58 has its left-hand end portion located in a manner as is illustrated in Fig. 8. From this latter figure it is to be seen that the lower cam 63 is in engagement with the top portion of the screw in a mannersuch that the plunger. 45 is raised to its highest position by the upper flat portion of the cam 60, while the plunger pin 57 is permitted. to drop downwardly into' a groove 80. With the pin 57 dropped to this position, as is illustrated in..Fig. 8, thethroat-plate 35 isreleased so that it may be removed-from beneath the plunger 45. By the same token, the plunger 46 is also shifted to its highest positiondue to the fact that thelower portion 51; of the plunger is positioned upon the upper flattened surfaceof the right-hand cam 61, whilethe plunger pin 57 is permitted to drop down in engagement with the upper surface 59 of the cam bar thusreleasing the righthand end portion ofthe throat-plate-to the end that the throat-plate maybe slipped away from the'plungers 45 andv 46 andxbe-completely released from the sewing machine. bed. Thereafter different throat-plates may be substituted.

Referring particularly to Figs. 1, 9and 10, there is provided an indicia plate 80 formed with anelongated slot 81, which plate isadapted to surround the throatplate actuating-handle 70 and to be secured to the bed portion of the machine by screws 75 and 82. As is illustrated in Fig. 10, the indicia plate 80 may be appropriately marked with the words Unlock, Up and Down to designate the three corresponding positions of the throat-plate actuating mechanism.

Having thus described, the nature of the invention, what I claim herein is:

1. In a sewing machine, a machine bed having a worksupporting surface formed with an aperture, a throatplate for closing the bed aperture and having an exposed work-supporting surface formed with a feed-dog receiving slo't, work-feeding means carried within the bed beneath the throat-plate and including a movable feed-dog which is normally operated in a path which extends through the throat-plate slot and beyond the exposed surface of the throat-plate, means carried by the bed and connected with the throat-plate for shifting the latter away from the bed to a location wherein the expo'sed throat-plate surface is disposed beyond the path of movement of the feed-dog and in parallelism with itself when in its closed position, quick-release means for releasing the throatplate from the last mentioned means whereby the throatplate may be removed from the machine, and an o'perator-influenced handle carried by the machine bed and connected witheach of the last-mentioned two means for operating such means.

2. In a sewing machine, a machine bed having-a worksupporting surface formed with an aperture, a throatplate for closing the bed aperture and having an exposed work-supporting surface formed with a feed-do'g'receiving slot, work-feeding means carried within the bed beneath the throat-plate and including a movable feed-dog which is normally operated in a. path which extends through the throat-plate slot and beyond .the exposedsurthereby to mainface of the throat-plate, means carried by the bed and connected with the throat-plate for shifting the latter away from the bed to a location wherein the exposed throat-plate surface is disposed above the path of movement of the feed-dog and in parallelism with itself when in its closed position, quick-release means for releasing the throat-plate from the last mentioned means whereby the throat-plate may be removed from the machine, and an operator-influenced handle carried by the machine bed and connected with each of the last-mentioned two means for operating such means, said handle having three predetermined positions of adjustment whereby when moved from one position to another it will sequentially shift the throat-plate from closed to open position and finally release the throat-plate from the machine.

3. In a sewing machine, a machine bed having a Worksupporting surface formed with an aperture, a throatplate for closing the bed aperture and havingan exposed wo'rk-supporting surface formed with a feed-dog receiving slot, a work-feeding means carried within the bed beneath the throat-plate and including a movable feed-dog which is normally operated in a path which extends through the throat-plate slot and beyond the exposed surface of the throat-plate, means carried by the bed and connected with the throat-plate for shifting the latter away from the bed to a location wherein the exposed throat-plate surface is disposed above the path of movement of the feed-dog and in parallelism with itself when in its closed position, such means comprising a pair of endwise shiftable elements mounted within the bed with one end of each element connected with the throat-plate, and operator-influenced means carried by the bed and connected with the other end of each of the elements for shifting the two elements in synchronism and endwise of themselves.

4. In a sewing machine as claimed in claim 3 and wherein each of the two endwise shiftable elements is releasably connected at its one end to the throat-plate, and means actuated by the operator-influenced means for disconnecting the throat-plate from the two shiftable elements whereby the throat-plate may be removed from the machine.

5. In a sewing machine as claimed in claim 3 and wherein the operator-influenced means is in the form of a handle shiftably mounted upon the bed, and wherein the handle is connected with each of the two elements by a unitary cam the movements of which are effective to shift the two elements back and forth relative to the bed.

6. In a sewing machine, a frame having a substantially horizontally extending hollow bed with a top horizontal work-supporting surface formed with an aperture, a throat-plate for closing the bed aperture and having an exposed horizontal work-supporting surface formed with a feed-dog receiving slot, Work-feeding means carried within the bed beneath the throat-plate and including a movable feed-dog which is normally operated in a vertical path which extends through the throat-plate slot and above the exposed surface of the throat-plate, and means carried by the bed and co'nnected with the throat-plate for shifting the latter upwardly away from the bed to a location wherein the exposed throat-plate surface is disposed above the path of movement of the feed-dog; such last mentioned means comprising a pair of plungers each mounted within the hollow bed for shiftable movements in a vertical direction, the upper ends of theplungers being connected with the throat-plate, an operator-influenced handle shiftably mounted upon the frame, and a unitary cam mounted within the bed for movements relative to the bed and connecting the handle with the lower ends of the two plungers whereby movements of the handle will be effective to raise and lower the throatplate by way of the plungers.

7. A sewing machine as claimed in claim 6 and comprising means provided at the upper ends of the two plungers for releasably engaging the throat-plate, and means connecting the last mentioned means with the cam whereby movement of the handle will sequentially raise the throat-plate and thereafter release the throat-plate from the plungers so that the throat-plate may be removed from the machine.

8. A sewing machine as claimed in claim 6 and comprising a pin slidingly mounted within and lengthwise of each plunger for releasably locking the throat-plate to the upper ends of the plungers, such pins being engageable with the cam element whereby movement of the handle will sequentially raise the throat-plate and thereafter unlock the throat-plate from the plungers so that the throat-plate may be removed from the machine.

References Cited in the file of this patent UNITED STATES PATENTS 791,384 Viglini May 30, 1905 2,144,801 Hohmann Ian. 24, 1939 2,723,638 Bell Nov. 15, 1955 FOREIGN PATENTS 254,064 Germany Nov. 21, 1912 482,468 Germany Sept. 14, 1929 740,831 Germany Oct. 29, 1943 

